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Date: Tue, 7 Jun 2016 12:38:41 +0530
From: Vinod Koul <vinod.koul@...el.com>
To: Kedareswara rao Appana <appana.durga.rao@...inx.com>
Cc: robh+dt@...nel.org, pawel.moll@....com, mark.rutland@....com,
ijc+devicetree@...lion.org.uk, galak@...eaurora.org,
michal.simek@...inx.com, soren.brinkmann@...inx.com,
dan.j.williams@...el.com, appanad@...inx.com,
moritz.fischer@...us.com, laurent.pinchart@...asonboard.com,
luis@...ethencourt.com, svemula@...inx.com, anirudh@...inx.com,
punnaia@...inx.com, devicetree@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
dmaengine@...r.kernel.org
Subject: Re: [PATCH v10 2/2] dmaengine: Add Xilinx zynqmp dma engine driver
support
On Wed, Jun 01, 2016 at 12:53:59PM +0530, Kedareswara rao Appana wrote:
> +config XILINX_ZYNQMP_DMA
> + tristate "Xilinx ZynqMP DMA Engine"
> + depends on (ARCH_ZYNQ || MICROBLAZE || ARM64)
> + select DMA_ENGINE
> + help
> + Enable support for Xilinx ZynqMP DMA controller.
Kconfig and makefile is sorted alphabetically, pls update this
> +#include <linux/bitops.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/dma/xilinx_dma.h>
> +#include <linux/dmaengine.h>
> +#include <linux/dmapool.h>
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/of_dma.h>
> +#include <linux/of_irq.h>
> +#include <linux/of_platform.h>
> +#include <linux/slab.h>
> +#include <linux/clk.h>
> +#include <linux/io-64-nonatomic-lo-hi.h>
do you really need so many headers?
> +static inline void zynqmp_dma_writeq(struct zynqmp_dma_chan *chan, u32 reg,
> + u64 value)
> +{
> +#if defined(CONFIG_PHYS_ADDR_T_64BIT)
> + writeq(value, chan->regs + reg);
> +#else
> + lo_hi_writeq(value, chan->regs + reg);
> +#endif
why do you need this? can you explain..
> +static inline bool zynqmp_dma_chan_is_idle(struct zynqmp_dma_chan *chan)
> +{
> + return chan->idle;
> +
empty line not required
> +static void zynqmp_dma_desc_config_eod(struct zynqmp_dma_chan *chan, void *desc)
eod? 80 line?
> + val = 0;
> + if (chan->config.has_sg)
> + val |= ZYNQMP_DMA_POINT_TYPE_SG;
why not val = and get rid of assign to 0 above
> + writel(val, chan->regs + ZYNQMP_DMA_CTRL0);
okay why write 0 for no sg mode?
> +
> + val = 0;
> + if (chan->is_dmacoherent) {
> + val |= ZYNQMP_DMA_AXCOHRNT;
> + val = (val & ~ZYNQMP_DMA_AXCACHE) |
> + (ZYNQMP_DMA_AXCACHE_VAL << ZYNQMP_DMA_AXCACHE_OFST);
> + }
> + writel(val, chan->regs + ZYNQMP_DMA_DSCR_ATTR);
same comments here too
> + spin_lock_bh(&chan->lock);
> + desc = list_first_entry(&chan->free_list, struct zynqmp_dma_desc_sw,
> + node);
how about:
desc = list_first_entry(&chan->free_list,
struct zynqmp_dma_desc_sw, node);
> + chan->desc_free_cnt++;
> + list_add_tail(&sdesc->node, &chan->free_list);
> + list_for_each_entry_safe(child, next, &sdesc->tx_list, node) {
> + chan->desc_free_cnt++;
> + INIT_LIST_HEAD(&child->tx_list);
> + list_move_tail(&child->node, &chan->free_list);
> + }
> + INIT_LIST_HEAD(&sdesc->tx_list);
why are you initializing list in free?
> +static int zynqmp_dma_alloc_chan_resources(struct dma_chan *dchan)
> +{
> + struct zynqmp_dma_chan *chan = to_chan(dchan);
> + struct zynqmp_dma_desc_sw *desc;
> + int i;
> +
> + chan->sw_desc_pool = kzalloc(sizeof(*desc) * ZYNQMP_DMA_NUM_DESCS,
> + GFP_KERNEL);
> + if (!chan->sw_desc_pool)
> + return -ENOMEM;
empty line here pls
> +static enum dma_status zynqmp_dma_tx_status(struct dma_chan *dchan,
> + dma_cookie_t cookie,
> + struct dma_tx_state *txstate)
> +{
> + return dma_cookie_status(dchan, cookie, txstate);
why do you need this wrapper, assign dma_cookie_status as your status
callback.
> +int zynqmp_dma_channel_set_config(struct dma_chan *dchan,
> + struct zynqmp_dma_config *cfg)
> +{
> + struct zynqmp_dma_chan *chan = to_chan(dchan);
> +
> + chan->config.ovrfetch = cfg->ovrfetch;
> + chan->config.has_sg = cfg->has_sg;
is this HW capability? if so why would anyone not like to use it!
> + chan->config.ratectrl = cfg->ratectrl;
> + chan->config.src_issue = cfg->src_issue;
> + chan->config.src_burst_len = cfg->src_burst_len;
> + chan->config.dst_burst_len = cfg->dst_burst_len;
can you describe these parameters?
How would a client know how to configure them?
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(zynqmp_dma_channel_set_config);
Not _GPL?
> + chan->bus_width = ZYNQMP_DMA_BUS_WIDTH_64;
> + chan->config.src_issue = ZYNQMP_DMA_SRC_ISSUE_RST_VAL;
> + chan->config.dst_burst_len = ZYNQMP_DMA_AWLEN_RST_VAL;
> + chan->config.src_burst_len = ZYNQMP_DMA_ARLEN_RST_VAL;
> + err = of_property_read_u32(node, "xlnx,bus-width", &chan->bus_width);
> + if ((err < 0) && ((chan->bus_width != ZYNQMP_DMA_BUS_WIDTH_64) ||
> + (chan->bus_width != ZYNQMP_DMA_BUS_WIDTH_128))) {
> + dev_err(zdev->dev, "invalid bus-width value");
> + return err;
> + }
> +
> + chan->bus_width = chan->bus_width / 8;
?
why not update it once?
--
~Vinod
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